January 17th is the Feast of San Antonio Abad, who is also known as San Antón in Spain. Although he was a hermit from Egypt, since Medieval times he has been the patron saint of domestic animals. To celebrate his feast, the night before and the day of the actual feast on January 17th, the Spanish build huge bonfires or hogueras in the streets, especially in Andalucia, Castilla-La Mancha, the Community of Valencia and Aragón. In Cataluna and the Balearic Islands, there are mounted processions in the streets. The townspeople gather around the bonfires, visit, eat, dance and drink.
Can the Spanish hold a festival without food? ¡Claro que no! Of course not! In towns like Trigueros (Huelva), townspeople throw legs of ham, bread and money as the religious procession for San Antonio makes its way through the streets and around the bonfires. In the area of Vega de Granada, in the province of Granada, the Olla de San Anton is prepared. It is a super stew containing lots of delicious, but high calorie ingredients, such as: beans, bacon, pigs feet, pigs ears and ribs, and morcilla sausage.
About.com's Guide to Spain has a very informative list of festivals, January Festivals in Spain - the Best Spanish Festivals in January.